I tried Brave recently due to deteriorating service from Chrome.
I have reported my own site not working with shields up because login to my own website on the following page does not work with shields up on Windows 10:
https://www.pets-n-friends.com/login.php
Our site is already working as an ‘app’ on its own hidden platform and thus login has to be cross domain capable even to login using Facebook. I presume some aspect of this cross domain software is the cause. If necessary I can share technical details on the advice of my associate who handles the login software.
One cannot rely on the general public to realise ‘shields up’ is the cause of a login button not working. If this issue can be solved, I will have our testers hold a full review of the site’s performance on Brave with a view to recommending the browser to our users.